Android : Option button not showing in action bar Android

I am trying to add action button , but they do not showing in action bar, they are display at button when click on hardware menu button . And the up button is also not working . i am sharing my code , tell me where i am wrong this is my manifest file :

    <application
    android:allowBackup="true"
    android:icon="@drawable/ic_launcher"
    android:label="@string/app_name"
    android:theme="@style/AppTheme" >
    <activity
        android:name=".MainActivity"
        android:label="@string/app_name"
       >
        <!-- Parent activity meta-data to support API level 7+ -->
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />
            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>

    <activity
        android:name=".secindActivity"
        android:label="Items"
        android:parentActivityName=".MainActivity" >
        <meta-data
            android:name="android.support.PARENT_ACTIVITY"
            android:value=".MainActivity" />
    </activity>

</application> 

I am adding the up button in second activity ,. it is showing but not working . And also trying to add action bar buttons in secondActivity . Menu file is as below :

      <?xml version="1.0" encoding="utf-8"?>

     <menu xmlns:Digicare="http://schemas.android.com/apk/res-auto"
    xmlns:android="http://schemas.android.com/apk/res/android">
 <item
    android:id="@+id/item_back"
    android:icon="@drawable/home2"
    Digicare:showAsAction="ifRoom"
    android:title="Home">

</item>
</menu>

These are problems . how to done this ????